How much is currently invested in artificial general intelligence research and development?
In the last years, there have been big investments in AI technologies. For an overview, maybe take a look at this article Artificial Intelligence: Investment Trends and Selected Industry Uses (2019).
A few companies that have the long-term goal of creating an AGI, although, currently, they mainly do research on specific problems (e.g. video games) or AI techniques (e.g. reinforcement learning), have received many funds. I will only list a few (maybe the most well-known ones) of these companies below, but there are probably many other companies that have this long-term goal and have been funded by other companies or people.
DeepMind
In their site, they write

Like the Hubble telescope that helps us see deeper into space, we aim to build advanced AI - sometimes known as Artificial General Intelligence (AGI) - to expand our knowledge and find new answers. By solving this, we believe we could help people solve thousands of problems.

DeepMind was acquired by Google in 2015 for $500 million, given its success in playing games at a superhuman performance, which is a promising step towards the development of more AI techniques and maybe AGI.
The Wikipedia article on DeepMind contains some information about people or companies that have invested in DeepMind, which includes companies Horizons Ventures and Founders Fund, and people  Scott Banister, Peter Thiel, Elon Musk, and Jaan Tallinn, although I cannot give you the exact numbers in terms of capital. In any case, serious investments have been done in DeepMind, which is definitely one of the promising companies that could develop good insights into the development of AGI systems.
OpenAI
Another company that has a similar goal and is doing research on similar topics (such as reinforcement learning or natural language processing) is OpenAI, which also has the long-term goal of creating AGI systems, as they write in their website

OpenAI’s mission is to ensure that artificial general intelligence (AGI) — by which we mean highly autonomous systems that outperform humans at most economically valuable work — benefits all of humanity. We will attempt to directly build safe and beneficial AGI, but will also consider our mission fulfilled if our work aids others to achieve this outcome.

Their investors include Microsoft, Reid Hoffman's charitable foundation, and Khosla Ventures.
Vicarious
They write in their site

Artificial general intelligence is the finish line on our journey toward progressively more capable robots. Our approach leverages deep expertise in neuroscience and is shaped by a decade of research.

They are apparently backed by more than 150 million dollars from people like Jeff Bezos, Elon Musk and Mark Zuckerberg and companies like Samsung.